It is well known in the art to provide clamps which are positioned after the assembly of the header box, the clamps having protruding lugs which are bent over or crimped by means of a press on the bearing flange of the header box, the pressure exerted by the press being such that a gasket interposed between the header box and the tube end plate is pressed for providing a suitable tightness between these two parts.
It has been found that the bending over or crimping of the clamp lugs is not accomplished, in practice, in a uniform manner, so that the lugs exert non uniform pressures on the header box. This disadvantage is further increased by the fact that the bending over or crimping of the clamp lugs often causes a deformation of the back portion of the clamp, which is due to stresses developed from the bent portion of the lugs.
It results from the hereabove mentioned factors that tightness defects can appear between the tube end plate and the header box covering it.
The present invention remedies this disadvantage.